Hi Paul, > > Or do we now have to discuss what this means: > > select * from t1 where NOT c1 NOT BETWEEN 2 AND 3! :P
:p Thanks to the standard, we don't. <where clause> ::= WHERE <search condition>, so: "NOT c1 NOT BETWEEN 2 AND 3" is a <search condition>. <search condition> ::= <boolean value expression>, so, it is also a <boolean value expression>. <boolean value expression> ::= <boolean term> | <boolean value expression> OR <boolean term> No OR in there, so it must be a <boolean term> <boolean term> ::= <boolean factor> | <boolean term> AND <boolean factor> Hey! we have an "AND" in there, so it could be that "NOT c1 NOT BETWEEN 2" is a <boolean term>, and "3" is a <boolean factor> Alternatively, the entire thing could also stil be a <boolean factor> <boolean factor> ::= [ NOT ] <boolean test> <boolean test> ::= <boolean primary> [ IS [ NOT ] <truth value> ] <truth value> ::= TRUE | FALSE | UNKNOWN Well, "3" is not a truth value, so we must accept that the entire thing is a <boolean factor>. In fact, from the production of <boolean factor> we can match the leading "NOT", so "c1 NOT BETWEEN 2 AND 3" must be a <boolean test> We don't see any "IS" in there, so we must conclude that "c1 NOT BETWEEN 2 AND 3" is a <boolean primary> <boolean primary> ::= <predicate> | <boolean predicand> So "c1 NOT BETWEEN 2 AND 3" is either a <predicate> or a <boolean predicand> <boolean predicand> ::= <parenthesized boolean value expression> | <nonparenthesized value expression primary> <parenthesized boolean value expression> ::= <left paren> <boolean value expression> <right paren> No parenthesis, so it is certainly not a <parenthesized boolean value expression>. It may still be a <nonparenthesized value expression primary>, but you all probably doze of if I prove that. So you're going to have to trust me that "c1 NOT BETWEEN 2 AND 2" is a predicate. <between predicate> ::= <row value predicand> <between predicate part 2> <between predicate part 2> ::= [ NOT ] BETWEEN [ ASYMMETRIC | SYMMETRIC ] <row value predicand> AND <row value predicand> More trust needed - c1 is a <row value predicand> In the remaining "NOT BETWEEN 2 AND 3", we can see "NOT" and "BETWEEN" and "AND", leaving us with "2" and "3" both being a <row value predicand>. Summing up: NOT (c1 NOT BETWEEN 2 AND 3) and not (NOT c1) NOT BETWEEN 2 AND 3 Phew, that sure makes me respect those SQL parsers. regards, Roland > > > -- > Paul McCullagh > PrimeBase Technologies > www.primebase.org > www.blobstreaming.org > pbxt.blogspot.com > > > > -- Roland Bouman http://rpbouman.blogspot.com/ _______________________________________________ Mailing list: https://launchpad.net/~drizzle-discuss Post to : [email protected] Unsubscribe : https://launchpad.net/~drizzle-discuss More help : https://help.launchpad.net/ListHelp
